Chainsaw mill bow

[Gog]

Evening all,

 

I need some advice please from anyone that does large boards with a chainsaw mill.

 

I have an ms880 with a 59" sthil bar and ripping chain. I have noticed that when I mill the boards they are never completely plat. There appears to be a bow in the board. Is this common when running such a long bar?

 

Kind regards

[billpierce]

Evening all,
 
I need some advice please from anyone that does large boards with a chainsaw mill.
 
I have an ms880 with a 59" sthil bar and ripping chain. I have noticed that when I mill the boards they are never completely plat. There appears to be a bow in the board. Is this common when running such a long bar?
 
Kind regards

Which way is the bow? From start to finish or sideways across the board?

Is it on yours first cut or something develops as you go through the log?

[gobbypunk]

Hi Bill , that ladder looks like it has a bend in it and there are not many wedges between the ladder and log this might allow the ladder to bow as you put weight on it, might be the cause.

[billpierce]

Swot I was thinking, support you ladder real good on first cut. Fix it down with screws. Eye it to check its level ( look right down it) and not bend or scewed.

[Gog]

The bow is on the bar of the chainsaw. The boards are perfect length wise but bow from side to Side. They are 3" consistent across but bowed.

Edited September 26, 2018 by Gog
Spelling error

[Gog]

The now is on the bar of the chainsaw. The boards are perfect length wise but bow from side to Side. They are 3" consistent across but bowed.  

 

It's hard to see but there is 15 100mm screws in the ladder holding it in position. See a rough drawn illustration of what I mean.

 

Kind regards

[Rough Hewn]

Take the mill off.
Is the bar bent?
Turn on it's side and rest the far end on a log.
Does the middle sag?
I can see the problem now!
You've left off the middle bar, the stainless tube!!!
Your whole mill is bending!
[emoji106][emoji106][emoji106]

[Gog]

The mill is made from 5mm inch X inch box. I thought this too but lay the mill on a flat surface and use a spirit level both box sections are perfectly straight. I personally think the sthil bar is sagging due to the length. I will check everything again to be certain.

 

Kind regards

[Rough Hewn]

Put the stainless bar back on.
A 59" bar shouldn't sag much.
The stainless bar adds tension and rigidity like a triangle.
[emoji106]

[Gog]

Perfect I will give this a try. It does make sense as it's perfect with the smaller bar. Thanks for your help.